scholarly journals Hotterdam: How space is making Rotterdam warmer, how this affects the health of its inhabitants, and what can be done about it

2015 ◽  
Author(s):  
Frank van der Hoeven ◽  
◽  
Alexander Wandl ◽  

Heat waves will occur in Rotterdam with greater frequency in the future. Those affected most will be the elderly – a group that is growing in size. In the light of the Paris heat wave of August 2003 and the one in Rotterdam in July 2006, mortality rates among the elderly in particular are likely to rise in the summer. METHOD The aim of the Hotterdam research project was to gain a better understanding of urban heat. The heat was measured and the surface energy balance modelled from that perspective. Social and physical features of the city we identified in detail with the help of satellite images, GIS and 3D models. We determined the links between urban heat/surface energy balance and the social/physical features of Rotterdam by multivariable regression analysis. The crucial elements of the heat problem were then clustered and illustrated on a social and a physical heat map. RESULTS The research project produced two heat maps, an atlas of underlying data and a set of adaptation measures which, when combined, will make the city of Rotterdam and its inhabitants more aware and less vulnerable to heat wave-related health effects. CONCLUSION In different ways, the pre-war districts of the city (North, South, and West) are warmer and more vulnerable to urban heat than are other areas of Rotterdam. The temperature readings that we carried out confirm these findings as far as outdoor temperatures are concerned. Indoor temperatures vary widely. Homes seem to have their particular dynamics, in which the house’s age plays a role. The above-average mortality of those aged 75 and over during the July 2006 heat wave in Rotterdam can be explained by a) the concentration of people in this age group, b) the age of the homes they live in, and c) the sum of sensible heat and ground heat flux. A diverse mix of impervious surfaces, surface water, foliage, building envelopes and shade make one area or district warmer than another. Adaptation measures are in the hands of residents, homeowners and the local council alike, and relate to changing behaviour, physical measures for homes, and urban design respectively.

2008 ◽  
Vol 47 (3) ◽  
pp. 819-834 ◽  
Author(s):  
Timothy M. Barzyk ◽  
John E. Frederick

Abstract Individual structures within the same local-scale (102–104 m) environment may experience different microscale (<103 m) climates. Urban microclimate variations are often a result of site-specific features, including spatial and material characteristics of surfaces and surrounding structures. A semiempirical surface energy balance model is presented that incorporates radiative and meteorological measurements to statistically parameterize energy fluxes that are not measured directly, including sensible heat transport, storage heat flux through conduction, and evaporation (assumed to be negligible under dry conditions). Two Chicago rooftops were chosen for detailed study. The City Hall site was located in an intensely developed urban area characterized by close-set high-rise buildings. The University rooftop was in a highly developed area characterized by three- to seven-story buildings of stone, concrete, and brick construction. Two identical sets of instruments recorded measurements contemporaneously from these rooftops during summer 2005, and results from the week of 29 July to 5 August are presented here. The model explains 83.7% and 96% of the variance for the City Hall and University sites, respectively. Results apply to a surface area of approximately 1260 m2, at length scales similar to the dimensions of built structures and other urban elements. A site intercomparison revealed variations in surface energy balance components caused by site-specific features and demonstrated the relevance of the model to urban applications.


2011 ◽  
Vol 3 (3) ◽  
pp. 204
Author(s):  
Taciana Lima Araujo ◽  
Enio Pereira Souza

O objetivo deste trabalho é estudar, através da modelagem numérica da atmosfera, os processos de superfície que determinam o saldo de radiação e a precipitação na zona urbana da cidade do Recife-PE. O modelo utilizado é o Brazilian developments on the Regional Atmospheric Modeling System - BRAMS. Uma melhora na representação dos processos de superfície em áreas urbanas foi obtida através do acoplamento entre o modelo BRAMS e um esquema específico para a representação da dinâmica urbana, o esquema Town Energy Budget - TEB. Foram realizados dois experimentos para testar a sensibilidade do modelo à representação da cidade. A consideração da superfície urbana aumenta o saldo de radiação sobre a cidade porque diminui o albedo da superfície e diminui a radiação de onda longa emitida. A influência das regiões urbanas nesses processos altera os fluxos de energia em superfície e, causa aumento da precipitação.Palavras-chave: BRAMS, região urbana, saldo de radiação.  Influence of the Surface Energy Balance and Intensity Urban Rainfall ABSTRACTThe objective of this work is to study the surface processes that determine the radiation budget and the precipitation at the urban area of the city of Recife-PE. The model used is the Brazilian developments on the Regional Atmospheric Modeling System - BRAMS. An improvement in the representation of the surface processes in urban areas was achieved through the coupling of the BRAMS model with a scheme suitable to representing the urban dynamics, the Town Energy Budget - TEB. Two experiments were run to test the model’s sensitivity to the city representation. The consideration of the urban surface increases the radiation budget over the city because it diminishes the surface albedo and the upcoming long wave radiation. The influence of the urban area alters the surface energy fluxes and increases the precipitation.Keywords: BRAMS, urban region, radiation budget


2016 ◽  
Vol 55 (11) ◽  
pp. 2369-2375 ◽  
Author(s):  
Dan Li ◽  
Ting Sun ◽  
Maofeng Liu ◽  
Linlin Wang ◽  
Zhiqiu Gao

AbstractThe interaction between urban heat islands (UHIs) and heat waves (HWs) is studied using measurements collected at two towers in the Beijing, China, metropolitan area and an analytical model. Measurements show that 1) the positive interaction between UHIs and HWs not only exists at the surface but also persists to higher levels (up to ~70 m) and 2) the urban wind speed is enhanced by HWs during daytime but reduced during nighttime as compared with its rural counterpart. A steady-state advection–diffusion model coupled to the surface energy balance equation is then employed to understand the implication of changes in wind speed on UHIs, which reveals that the observed changes in wind speed positively contribute to the interaction between UHIs and HWs in both daytime and nighttime. The vertical structure of the positive interaction between UHIs and HWs is thus likely an outcome resulting from a combination of changes in the surface energy balance and wind profile.


2011 ◽  
Vol 4 (3) ◽  
pp. 589 ◽  
Author(s):  
Elvis Bergue Mariz Moreira ◽  
Ranyére Silva Nóbrega ◽  
Bernardo Barbosa da Silva

O conhecimento do saldo de radiacao em areas urbanas e fundamental em estudos de monitoramento de mudanças climaticas e pode ser um indicador de urbanizacao vivenciando por uma determinada area, contudo apresenta-se no campo das pesquisas cientificas pouco exploradas. O principal objetivo desse trabalho foi a obtencao do saldo de radiacao instantaneo na cidade do Recife. Para tanto, foram utilizadas duas imagens do Mapeador Tematico do satélite Landsat 5 referente as datas 26 de agosto de 2006 e 06 de setembro 2010 na orbita e ponto 215/66. As imagens foram processadas atraves do algoritmo SEBAL (Surface Energy Balance Algorithm for Land) que e baseado na irradiacao medida nos canais reflectivos (1,2,3,4,5 e 6). Os resultados encontrados apontaram para as imagens em estudo, os menores valores do (Rn) nas areas urbanas e os maiores foram encontrados nas areas com vegetacao e corpos hidricos. A cena referente ao ano de 2006 apresentou na area urbana valores de (Rn) inferiores a 692 Wm-2 , enquanto o ano de 2010 apresentou 730 Wm-2. De modo geral, os maiores valores de (Rn) foram encontrados na imagem de 2010, tal aumento pode esta associado a saxonalidade da radiacao solar. Palavras chaves: radiacao solar, sensoriamento remoto, algoritmo sebal  Estimation of Instantaneous Radiation Balance in City of Recife, Via Satellite Images LANDSAT 5 TM    ABSTRACT  Knowledge of the radiation balance in urban areas is essential in monitoring studies of climate change and can be an indicator of urban living for a certain area, but has in the field of scientific research unexplored. The main objective of this work was to obtain the instantaneous net radiation in the city of Recife. Therefore, we used two images from Landsat Thematic Mapper 5 for the dates August 26, 2006 and September 6, 2010 point in the orbit and 215/66. The images were processed through the algorithm SEBAL (Surface Energy Balance Algorithm for Land) which is based on irradiation as reflective channels (1,2,3,4,5 and 6). The results pointed to the images under study, the lowest values of (Rn) in urban areas and the largest were found in areas with vegetation and water bodies. The scene for the year 2006 presented in the urban area values (Rn) of less than 692 Wm-2, while the year 2010 showed 730 Wm-2. In general, the highest values of (Rn) were found in the image of 2010, this increase is associated with can saxonalidade solar radiation.  Keywords: solar radiation, remote sensing, algorithm sebal


2014 ◽  
Vol 7 (4) ◽  
pp. 653
Author(s):  
Silvia Cristina De Pádua Andrade ◽  
Jéssica Ariana De Jesus Corrêa

A estimativa do saldo de radiação (Rn) em ambientes urbanos é de fundamental importância para o entendimento e a quantificação dos impactos que as estruturas presentes nas áreas urbanas causam nas trocas de energia entre a superfície e a atmosfera. Assim, o presente trabalho teve por objetivo estimar o saldo de radiação instantâneo à superfície no perímetro urbano do município de Santarém, no estado do Pará, utilizando para isto o algoritmo SEBAL (Surface Energy Balance Algorithm for Land) e duas imagens do satélite Landsat 5 - TM, correspondentes aos dias 02 de agosto de 1999 e 29 de junho de 2010. Os resultados obtidos mostraram que as áreas urbanas apresentaram os maiores valores de albedo e temperatura da superfície, e menores valores de NDVI e do saldo de radiação, enquanto que em áreas com vegetação e corpos d’água, estes valores se invertem. Na cena de 1999, os valores mínimo e máximo do Rn foram 296 e 697 W m-2, e para 2010 foram 161 e 682 W m-2, respectivamente. Observou-se uma diminuição no saldo de radiação na imagem de 2010, com maior espacialização de valores compreendidos na faixa entre 472 e 522 W m-2. De modo geral, pode-se atribuir a diminuição do (Rn) encontrado na cena de 2010, a mudança da cobertura do solo e a sazonalidade da radiação solar no momento da passagem do satélite sobre a área em estudo.   ABSTRACT: The estimate of net radiation (Rn) in urban environments is of fundamental importance for the understanding and quantification of the structures in urban areas causing the exchange of energy between the surface and the atmosphere. Thus, this study aimed to estimate the balance of instantaneous surface radiation in the urban area of the municipality of Santarem, in Para state, using for this purpose the algorithm SEBAL (Surface Energy Balance Algorithm for Land) and two images of Landsat 5 - TM, corresponding to the days August 2, 1999 and June 29, 2010. The results showed that urban areas presented the highest values of albedo and surface temperature, and lower values of NDVI and net radiation, while in areas with vegetation and water bodies, these values are reversed. In the scene of 1999, the minimum and maximum Rn values were 296 and 697 W m-2 respectively, and 2010 were 161 and 682 W m-2, respectively. There was a decrease in net radiation at the picture of 2010 with higher spatial values included in the range between 472 and 522 W m-2. In general, one can attribute the decrease of (Rn) found at the scene of 2010, the change of land cover and seasonality of solar radiation at the time the satellite passed over the area under study. Keywords: urbanization, net radiation, albedo, remote sensing, SEBAL.  


2021 ◽  
pp. 1-19
Author(s):  
Rebecca L. Stewart ◽  
Matthew Westoby ◽  
Francesca Pellicciotti ◽  
Ann Rowan ◽  
Darrel Swift ◽  
...  

Abstract Surface energy-balance models are commonly used in conjunction with satellite thermal imagery to estimate supraglacial debris thickness. Removing the need for local meteorological data in the debris thickness estimation workflow could improve the versatility and spatiotemporal application of debris thickness estimation. We evaluate the use of regional reanalysis data to derive debris thickness for two mountain glaciers using a surface energy-balance model. Results forced using ERA-5 agree with AWS-derived estimates to within 0.01 ± 0.05 m for Miage Glacier, Italy, and 0.01 ± 0.02 m for Khumbu Glacier, Nepal. ERA-5 data were then used to estimate spatiotemporal changes in debris thickness over a ~20-year period for Miage Glacier, Khumbu Glacier and Haut Glacier d'Arolla, Switzerland. We observe significant increases in debris thickness at the terminus for Haut Glacier d'Arolla and at the margins of the expanding debris cover at all glaciers. While simulated debris thickness was underestimated compared to point measurements in areas of thick debris, our approach can reconstruct glacier-scale debris thickness distribution and its temporal evolution over multiple decades. We find significant changes in debris thickness over areas of thin debris, areas susceptible to high ablation rates, where current knowledge of debris evolution is limited.


2020 ◽  
pp. 1-16
Author(s):  
Tim Hill ◽  
Christine F. Dow ◽  
Eleanor A. Bash ◽  
Luke Copland

Abstract Glacier surficial melt rates are commonly modelled using surface energy balance (SEB) models, with outputs applied to extend point-based mass-balance measurements to regional scales, assess water resource availability, examine supraglacial hydrology and to investigate the relationship between surface melt and ice dynamics. We present an improved SEB model that addresses the primary limitations of existing models by: (1) deriving high-resolution (30 m) surface albedo from Landsat 8 imagery, (2) calculating shadows cast onto the glacier surface by high-relief topography to model incident shortwave radiation, (3) developing an algorithm to map debris sufficiently thick to insulate the glacier surface and (4) presenting a formulation of the SEB model coupled to a subsurface heat conduction model. We drive the model with 6 years of in situ meteorological data from Kaskawulsh Glacier and Nàłùdäy (Lowell) Glacier in the St. Elias Mountains, Yukon, Canada, and validate outputs against in situ measurements. Modelled seasonal melt agrees with observations within 9% across a range of elevations on both glaciers in years with high-quality in situ observations. We recommend applying the model to investigate the impacts of surface melt for individual glaciers when sufficient input data are available.


Atmosphere ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 46
Author(s):  
Reija Ruuhela ◽  
Athanasios Votsis ◽  
Jaakko Kukkonen ◽  
Kirsti Jylhä ◽  
Susanna Kankaanpää ◽  
...  

Urbanization and ongoing climate change increase the exposure of the populations to heat stress, and the urban heat island (UHI) effect may magnify heat-related mortality, especially during heatwaves. We studied temperature-related mortality in the city of Helsinki—with urban and suburban land uses—and in the surrounding Helsinki-Uusimaa hospital district (HUS-H, excluding Helsinki)—with more rural types of land uses—in southern Finland for two decades, 2000–2018. Dependence of the risk of daily all-cause deaths (all-age and 75+ years) on daily mean temperature was modelled using the distributed lag nonlinear model (DLNM). The modelled relationships were applied in assessing deaths attributable to four intensive heatwaves during the study period. The results showed that the heat-related mortality risk was substantially higher in Helsinki than in HUS-H, and the mortality rates attributable to four intensive heatwaves (2003, 2010, 2014 and 2018) were about 2.5 times higher in Helsinki than in HUS-H. Among the elderly, heat-related risks were also higher in Helsinki, while cold-related risks were higher in the surrounding region. The temperature ranges recorded in the fairly coarse resolution gridded datasets were not distinctly different in the two considered regions. It is therefore probable that the modelling underestimated the actual exposure to the heat stress in Helsinki. We also studied the modifying, short-term impact of air quality on the modelled temperature-mortality association in Helsinki; this effect was found to be small. We discuss a need for higher resolution data and modelling the UHI effect, and regional differences in vulnerability to thermal stress.


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